The present invention relates to a calculating machine such as an electronic cash register. More particularly, the present invention relates to a data reproduction-level detecting device adapted to the calculating machine.
Recently, an audio cassette tape has been employed for storing data in the form of analog information useful for an electronic apparatus of a stored program system. In introducing data from the audio cassette tape to an entry means of the electronic cash register, the data has previously been taken out through earphone terminals connected to a sound volume adjustment circuit for a cassette tape deck. Therefore, adjustment of sound volume greatly affects the reliability of the data introduced.
The sound volume of the data from the cassette tape deck to the entry means of the electronic apparatus has been controlled by changing volume in the cassette tape deck. The control of the volume in the cassette tape deck was conducted with the help of only perception of the operator. When the data once entered into the entry means did not have an appropriate reproduction level and, accordingly, error was detected, the operator was informed of the presence of error and had to repeat the entry operation of the data from the beginning.